Streaming

ABSTRACT

Liquid is mixed with a gas in a chamber of diameter large relative to a nozzle sculpted in boundary layer downstream thereof, the liquid entering the chamber through holes in a plate at an upstream end of the housing.

United States Patent Nathaniel Hughes Beverly Hills, Calif. 778,145

Nov. 22, 1968 Jan. 19, 1971 Energy Sciences, Inc.

El Segundo, Calif.

a corporation of California inventor Appl. No. Filed Patented Assignee STREAMING 6 Claims, 4 Drawing Figs.

US. Cl 239/102,

239/429, 239/433 Int. Cl B05b 3/14 Field ofSearch 239/102,

[56] References Cited UNITED STATES PATENTS 2,008,232 7/1935 Walker 239/429X 2,879,948 3/1959 Seibel 239/4275 3,240,254 3/1966 Hughes 239/ 102X 3,334,657 8/1967 Smith et al 239/102X Primary ExaminerM. Henson Wood, Jr. Assistant Examiner.l0hn J. Love Attorney-William W. Rymer ABSTRACT: Liquid is mixed with a gas in a chamber of diameter large relative to a nozzle sculpted in boundary layer downstream thereof, the liquid entering the chamber through holes in a plate at an upstream end of the housing.

PATENTEU JAN 1 91971 STREAMING This invention relates to streaming at supersonic speeds using small nozzles of the general character disclosed in the pending applications of Nathanial Hughes, Ser. No. 718,447, filed Apr. 3. 1968, now US. Pat. No. 3,531.048 Supersonic Streaming," and Ser. No. 734,089, filed June 3, 1968, now Pat. No. 3,542,291 Streaming. in which effective nozzle surfaces within essentially cylindrical bores are defined by boundary layer effects.

Objects of the invention are to increase the intensity of the shock process at the outlet of such nozzles and to provide for better atomization of liquid treated thereby. In preferred embodiments in jet aircraft engines other objects are to provide.

effective pretreatment of liquid to be atomized, to enable processing of large quantities of fuel even at low air pressure and flow rate during engine startup, and to increase fuel combustion efficiency.

The invention features a housing defining a mixing chamber of diameter large relative to such a nozzle downstream thereof, a plate at an upstream end of the housing and providing small liquid inlet holes, gas inlet holes in the housing downstream of the plate, and the nozzle mounted opposite the plate downstream of the gas and liquid inlet holes. In preferred embodiments at least one liquid inlet hole is slanted to cause the stream of liquid issuing therefrom to strike a liquid stream issuing from another inlet hole, a first plurality of liquid inlet holes are disposed around an axis toward which they are slanted, a second plurality of liquid inlet holes are closer to said axis and have their own axes parallel thereto, and each liquid inlet hole has an upstream portion of enlarged flow cross section.

Other objects, advantages, and features of the invention will be apparent from the following description of a preferred embodiment thereof, taken together with the drawings, in which:

FIG. 1 is a side view, mostly in section, of a portion of a jet aircraft engine embodying the invention;

FIG. 2 is an exploded isometric view thereof;

FIG. 3 is a sectional view through the longitudinal axis of the nozzle shown as a part of FIGS. 1 and 2; and

FIG. 4 is an end view, partially broken away, of the nozzle of FIG. 3.

Referring to FIGS. 1 and 2, nozzle nut is screwed over fuel-metering plate 12 and onto pedestal 14, which communicates with a fuel manifold (not shown) through passages 16 and 18. Passages 16 and 18 respectively feed fuel oil to annular recess 20 and bore 22 concentric therewith in pedestal 14. Four oblique fuel inlet holes 30 (each 0.043 inch in diameter) equally spaced circumferentially in plate 12 communicate with recess 20 through enlarged passages 38 (two of which are shown in FIG. 1). Two fuel inlet holes 50 (each 0.02 inch in diameter) communicate through enlarged passages 54 with bore 22.

Forward of plate 12 nut 10 extends into combustion can 58 (a fragment of which is shown in FIG. 1) and defines mixing chamber 60, through the wall of which, outside can 58, extend air inlet holes 62.

Nozzle 70 is welded in countersunk circular opening 72 in front wall 73 of nut 10 centrally of a ring of oblique exit holes 74. Generally annular shroud 76 extends out from nut 10 and bends around in front of holes 74 and then back in toward wall 73 and nozzle 70, defining a zone 78.

Central inlet hole 82 extends through rear wall 80 of nozzle 70 and is concentric with an imaginary circle containing the centers of eight equally spaced smaller inlet holes 84 arranged in pairs, toward opposite ends of diameters of nozzle 70. Cylindrical boundary layer confining wall 88 has, toward its outlet, four radial throat stabilizing holes 90, with coplanar axes spaced 90 from one another. The front of the nozzle is open to the interior of can 58, and includes 45 countersink 100.

'In operation, JP-4 jet engine fuel is introduced through holes 30 and 50 into relatively large chamber 60 to mix with air entering through holes 62. The angular relationship of holes 30 causes the streams of fuel to hit one another, improving the mixing. At engine startup the inlet air pressure is e.g.,

0.2 p.s.i.g., air flow is at a rate of 8 lbs./hr., and fuel flow is at a rate of lbs/hr. These FIGS. may increase respectively to 12 5 p.s.i.g., 200 lbs/hr. and 1100 lbs/hr. during steady operation, after startup. Part of the compressible air fuel mixture passes through inlet hole 82 into the nozzle defined by boundary layer confined within wall 88. Fluid mixture also moves outside wall 88 and through holes 90 to stabilize the plane of the throat of the nozzle sculpted in boundary layer in the manner taught in the said patent applications. Another part of the mixture passes through holes 84 each of which is small enough to promote within its own confining cylindrical wall sufficient boundary layer growth to provide barely supersonic flow. (Flow within boundary layer confining wall 88 in said nozzle helps to speed up the flow through the holes 84 by increasing the pressure drop thereacross.)

The characteristic burst frequencies of the main portion of said nozzle, and of the streams leaving holes 84, produce a superheterodyne effect, with resultant beats which may be measured, for example to monitor functioning.

The rest of the mixture in chamber 60 passes through holes 74 into zone 78 and implodes under compressible fluid pressure into the nozzle outlet zone, increasing the shock effects and work done there, and improving atomization.

The included cone angle of the atomized stream, under flow conditions already set forth, is 70 during startup and before ignition, and about 140 at initial ignition, the doubling being attributable to the great intensity of heat owing to localization (through efficient atomization and mixing) of the zone of combustion. During steady operation, after startup, at flow rates above specified, the ignited cone angle may be about 85.

The preferred embodiment, used in a jet aircraft engine as described, enables the efficient processing of large quantities of fuel even during engine startup when air inlet pressure and flow rate are low. Smoking is reduced, and ignition is facilitated by wide cone angles.

The diameter of hole 82 or the number of holes 84 can be increased to obtain even wider cone angles. Holes 84 must always, however, be arranged in pairs along diameters of hole 82.

Nozzle parameters are calculated in the manner set forth in said pending applications. In the preferred embodiment, the parameters are:

Inch

Each hole 84 has a diameter and length of 0.032 inch. The centerlines of opposing pairs of holes 84 are 0.226 inch apart.

Other embodiments will occur to those skilled in the art and are within the following claims.

I claim:

1. An atomizer comprising a housing defining a chamber of diameter greater than the diameter of a supersonic nozzle downstream thereof;

a plate at an upstream end of said housing and providing therethrough a plurality of liquid inlet holes;

said nozzle mounted opposite said plate and downstream thereof, means to provide a supersonic jet through said nozzle, said means including a boundary layer confining wall and an inlet and outlet with a throat plane stabilizer therebetween; and

said housing having gas inlet holes adjacent but radially outward of and downstream of said plate, and said nozzle inlet being downstream of said holes.

2. The atomizer of claim 1 in which at least one said liquid inlet hole is slanted to cause a liquid stream issuing therefrom 75 to hit a liquid stream issuing from another said inlet hole.

3. The atomizer of claim 2 in which there are a plurality of said liquid inlet holes disposed around an axis and slanted to direct liquid streams respectively issuing therefrom toward said axis.

4. The atomizer of claim 3 in which there are an additional plurality of said liquid inlet holes closer to said axis than are 

1. An atomizer comprising a housing defining a chamber of diameter greater than the diameter of a supersonic nozzle downstream thereof; a plate at an upstream end of said housing and providing therethrough a plurality of liquid inlEt holes; said nozzle mounted opposite said plate and downstream thereof, means to provide a supersonic jet through said nozzle, said means including a boundary layer confining wall and an inlet and outlet with a throat plane stabilizer therebetween; and said housing having gas inlet holes adjacent but radially outward of and downstream of said plate, and said nozzle inlet being downstream of said holes.
 2. The atomizer of claim 1 in which at least one said liquid inlet hole is slanted to cause a liquid stream issuing therefrom to hit a liquid stream issuing from another said inlet hole.
 3. The atomizer of claim 2 in which there are a plurality of said liquid inlet holes disposed around an axis and slanted to direct liquid streams respectively issuing therefrom toward said axis.
 4. The atomizer of claim 3 in which there are an additional plurality of said liquid inlet holes closer to said axis than are said slanted holes.
 5. The atomizer of claim 4 in which said additional holes have their axes parallel to the first-mentioned axis.
 6. The atomizer of claim 1 in which each said inlet hole has an upstream portion with an enlarged flow cross section. 